The field of this invention is "oral compositions" which term is used herein to designate products which in the ordinary course of usage are retained in the oral cavity for a time and in a manner sufficient to contact essentially all of the dental surfaces, but are not intentionally ingested. Such products include, for example, dentifrices, mouthwashes, prophylaxis pastes and topical solutions.
The bis-biguanide antibacterial agents such as chlorhexidine, 1,6 bis(N.sup.5 -p-chlorophenyl-N.sup.1 -biguanido) hexane, are known to be effective antiplaque agents, but it has been recognized that they have a tendency to produce severe staining of the teeth. Belgian Pat. No. 801,703, issued Jan. 4, 1973, discloses the use of the insoluble salts of the bis-biguanides in oral compositions as a means of reducing the stain problem. Belgian Pat. No. 811,878, issued Sept. 4, 1974, U.S. patent application Ser. No. 495,951, filed Aug. 9, 1974, (and its continuation-in-part Ser. No. 584,304, filed June 6, 1975) and U.S. patent application Ser. No. 563,988, filed Apr. 1, 1975, (and its continuation-in-part Ser. No. 652,092, filed Jan. 27, 1976) disclose the use of metal ion chelator compounds, such as amino acids, aminopolycarboxylates and hydroxypyrones, with the bis-biguanides to reduce stain. My concurrently-filed copending application having Ser. No. 670,518 (continuation-in-part of Ser. No. 589,232, filed June 23, 1975) discloses certain bisbiguanides, wherein the bridging alkylene group has from 1 to 4 carbon atoms instead of six, which have substantially lower staining tendencies then chlorhexidine.